The research on improving the spatial resolution of radiant optical fiber temperature sensor

A method to improve the spatial resolution of the radiant optical fiber temperature sensor is proposed in this paper. The front lens of the sensor is designed to limit the diameter of the thermometry target. In order to avoid limiting the influence of the thermometry target diameter on the sensor radiation-light coupling ability, a mathematical model of the radiation-light coupling of the sensor is established, and the relationship between the radiation-light coupling ability of the sensor and the diameter of the thermometry target is analyzed. Furthermore, an aspheric lens is applied to reduce the influence of aberration on the diameter of the thermometry target. The experimental results show that the deviation between the actual temperature measuring target diameter and the theoretical design value is less than 0.2 mm. The radiation received by the sensor outside the temperature measuring target is less than 10% of its total received radiation. Moreover, when there is radiated light interference outside the temperature measurement target, the temperature measurement error of the sensor is only 0.21%-2.61%, indicating that the proposed method has practical significance in improving the spatial resolution of the temperature measurement.